It is well known to provide house installation electrical cables to be installed in concrete or cement based materials. Such a cable may be for example a heating cable to be installed in floors and walls for the general heating of buildings, and in outdoor pavements, for snow melting purposes. Such a heating cable comprises a resistance conductor with a relatively high positive temperature coefficient (PTC), the resistance conductor becoming warm when sufficient current flows through it. Such a cable may also be a power or telecommunication cable.
One problem is to prevent a house installation electrical cable, intended to be installed in concrete or similar cement based materials in floors, to float up to the surface of the wet concrete during installation, which limits the need to attach the cable to the existing floor surface
A known solution to this problem is to provide an electrical cable having an inner sheath made of lead. Lead is indeed a heavy weight material avoiding such heating cable to float up to the surface and limits the need to attach it to the existing floor
This solution raises some difficult problems because of environmental reasons. At some levels of human exposure to lead, there is indeed a risk of damage for human organ systems and biochemical processes. Therefore, introduction of lead into the human environment has decreased in recent years, largely due to public health campaigns.